This invention pertains to an orthodontic connector device, and more particularly, to a rigid, grommet-like end connector device for use with an end of one or more elastomeric orthodontic, tension-applying chains of the kind having a string of plural, endless, stretchable loops.
There are many instances in the practice of orthodontics where it is necessary to apply what are known as intermaxillary forces: for example, to correct the relative positions of the upper and lower jaws in Class II and Class III malocclusions. In these kinds of applications, because of the wide range of relative movement permitted between upper and lower jaws, a force-applying elastomer extending between connection points provided on the jaws can be subjected to extensive stretching and relaxing, and to major abrasive wear at its end connections. What this means, in terms of effective force application between visits to an orthodontist, is that the wearer must be responsible at regular and relatively frequent intervals to replace worn elastomers faithfully. However, experience has shown that such faithful attention is often not paid by a user, and as a consequence, the final desired result of the related orthodontic procedure is delayed.
A general object of the present invention is to provide a unique end-connector device for use with one or more conventional so-called orthodontic elastomer chains, which device, in a simple and practical manner, obviates the problem of end-connection wear, as outlined above, and promotes the use of multiple parallel-connected chain elastomers, if necessary, to provide an overall long-life force-applying assembly which need not be attended to, except in unusual circumstances, between regular visits to an orthodontist.
The device is designed herein primarily for use with conventional elastomer chains, inasmuch as such chains offer an extremely wide range of elastic stretchability, and are particularly well suited to intermaxillary procedures of the type generally set forth above.
According to a preferred embodiment of the invention, which takes the form what is referred to herein as a rigid grommet-like, end-connector device, the same includes first and second eyelet portions which are joined through an offset gooseneck-like expanse, or stretch, formed integrally with the eyelet portions. The first eyelet portion has a body of revolution, with a generally planar circumferential groove that is designed to receive an end loop in one or more chains of the type mentioned. Extending through the first eyelet portion, along the axis of revolution of its body of revolution, is an aperture which is substantially normal to the plane of the groove--this aperture being adapted for attachment to an external orthodontic appliance, such as a hook mounted on a conventional tooth band. The second eyelet portion is radially offset from the first eyelet portion, to one side of the groove just described, with the second eyelet portion including an aperture extending through it along an axis which is generally radial with respect to the axis of revolution of the first eyelet portion, and which generally occupies the plane of the groove in the first eyelet portion. This second-mentioned aperture is adapted threadably to receive an end portion of a chain whose end loop is mounted in the groove. It functions to guide such an end portion away from the end loop, in a manner resisting removal of the loop from the groove, and in a further manner shrouding or encasing such end portion to protect it against abrasive wear.
The device of the invention offers a number of important advantages, which should be clear from a consideration of the proposed construction just set forth. Where a single chain length is deemed adequate for a particular application, use of an end-connector device made in accordance with the invention, at both ends of such a length, provides for extremely low-wear end-connections for the chain length. Where two or more parallel-connected chains are deemed appropriate for the application, the groove in the proposed device accommodates easy attachment of these, and, as in the single-chain-length application just referred to, the end portions of these multiple chain lengths are afforded low-wear end-connections.